1. Field of the Invention
The present invention relates to an improvement in a camera using a film with a magnetic memory portion, in which information is written to or read from the magnetic memory portion of the film. More specifically, the present invention pertains to a head movement feature for such a camera.
2. Description of the Related Art
A camera using a film with a magnetic memory portion has been disclosed in U.S. Pat. No. 4,878,075. This camera is arranged to be able to write information pertaining to a shutter time, an aperture value, a date of year, month and day, etc., to the magnetic memory portion, to read out either the same written information, or information previously written, pertaining to the ISO, the specified number of film frames, etc., by means of a magnetic head in contact with the magnetic memory portion of the film during a transporting operation of the film.
However, the magnetic head, which is merely in the reading or writing position, or in actual contact with the magnetic memory portion of the film, causes the following problems.
(1) In a film cartridge completely containing the whole roll of film therein, including the leader part of the film, when the film is thrust out of the cartridge by driving its shaft with a fork after the film cartridge is inserted into a cartridge chamber, as disclosed in U.S. Pat. No. 4,841,319, the leader part of the film runs into the magnetic head while the film is thrust out from the cartridge, and an automatic film loading operation becomes impossible;
(2) If the magnetic head is in pressure contact with the film for a long time, the film will become deformed; and
(3) If the magnetic head is in pressure contact with the film during an exposure operation, the film surface becomes uneven with the result that the image quality of a photograph made from the film deteriorates.
In order to solve these problems, the applicant has proposed in U.S. patent application Ser. No. 633,997 a camera wherein either the magnetic head or a pad holding the film between the magnetic head and the pad is moved away from the film excluding the interval when the information is written to or read from the magnetic memory portion of the film.
However, the aforementioned camera has the following problems.
(1) The camera is arranged to position the magnetic head on the side of the back lid of the camera and to position the pad on the side of the photographic lens of the camera across the film because the magnetic memory portion of the film is provided on the side of the base side of the film.
Additionally, the magnetic memory portion is provided at a location corresponding to a photographic frame of the film.
For these reasons, in a type of conventional camera having a focal-plane shutter, such as a single-lens reflex camera, the mechanism moving the pad away from the film interferes with the focal-plane shutter. Consequently, such a camera cannot function properly.
(2) Regarding the mechanism for moving the magnetic head away from the film, a motor used as a driving source for moving the magnetic head away from the film is arranged on the side of the magnetic head, i.e., on the side of the back lid of the camera. This makes the size of the camera on the side of the back lid very large. That is, the camera becomes bulky in this area.
Further, the camera disclosed in the aforementioned U.S. patent application Ser. No. 633,997 has the following problems for the reason that the film moves up and down in a wave-like motion while being transported.
(1) The up and down wave-like motion causes a positional deviation perpendicular to the film supply direction between the magnetic head and the magnetic memory portion of the film. Therefore, the photographic information cannot be accurately written to and read from the magnetic memory portion of the film.
(2) The magnetic gap of the magnetic head must make contact with the magnetic memory portion of the film as perpendicularly as possible to a film transporting direction. However, the above-stated motion of the film lowers the degree of perpendicularity of the magnetic gap of the magnetic head relative to the film transporting direction.
In order to solve these problems,the applicant has proposed in U.S. patent application Ser. No. 634,102 a camera having a following mechanism for causing the magnetic head follow the up and down wave-like motion of the film.
However, when the following mechanism is combined in a non-interfering fashion with the magnetic head moving-away mechanism disclosed in the aforementioned U.S. patent application Ser. No. 633,977, the camera becomes large and complicated.